The present invention relates generally to vibratory finishing, grinding, polishing and deburring machines of the type which generally comprises annular or toroidal finishing chamber or bowl that is partially filled with a mass of workpieces and finishing media and which is caused to vibrate in a predetermined manner in order to "finish" or debur the workpieces. Such finishing machines are generally shown in U.S. Pat. Nos. 3,100,088; 3,266,739; 3,268,177; 3,161,993 and 3,893,266. More particularly, the present invention relates to a new and improved method and apparatus for separating the workpieces from the media and unloading the workpieces from the finishing bowl in a manner so as to obviate the need for manual handling of the workpieces and/or media.
Heretofore, the separation and removal of finished workpieces from the media in vibratory finishing machines has been accomplished in two generally accepted methods. In one method, the parts and media are conveyed in a generally vertical plane by various types of devices whereby the workpieces and media are deposited on a machine mounted screen or separation purposes, resulting in the media dropping downwardly into the a special chamber adjacent the finishing chamber for the reintroduction into the finishing vessel after the separating cycle. In the second method, the configuration of the finishing compartment is such that the handling of the workpieces and media is in a generally horizontal fashion with the finishing compartment having a spiral or circular ramp arrangement adapted to convey the workpieces and media to a sufficient elevation to make possible installation of the workpiece-from-media separation facility. Neither of these methods, however, has been found to be completely satisfactory insofar as removing and separating workpieces from vibratory finishing machines of the type having circular or bowl-type finishing chambers due to the many difficulties involved in applying or installing the workpiece removing apparatus. Furthermore, in most cases, the unloading apparatus has had to be manually installed and removed at the time each unloading operation was to occur which prevented the machine from being automated so that the workpieces could be removed without an operator being in attendance.
The present invention is intended to overcome the shortcomings of prior known and used workpiece separating and unloading devices and utilizes a novel dam or weir which is mounted by means of a pivot arm secured at a central position within the finishing bowl. The weir and pivot arm are selectively pivotable and rotatable from a first position wherein the weir is located above the surface of the workpiece-media mixture so that the mixture may move around the finishing bowl beneath a generally horizontally disposed separating screen during a normal finishing operation, and a second lower position wherein the weir extends generally transversely of the path of movement of the workpiece-media mixture at a position directly upstream from the separating screen. When the weir is disposed in its lower position, the workpiece-media mixture is caused to move onto the upper surface of the separating screen and the workpieces are conveyed away from the finishing bowl, while the media drops downwardly through the separating screen and is returned to the interior of the finishing bowl. Movement of the weir between the aforesaid elevated or raised and lower positions is achieved through the provision of a piston and cylinder assembly, with the pressure of the workpiece-media mixture acting to selectively rotate the weir to a vertical position as it moves downward toward its unloading position. The entire assembly may be operated without the need for an operator in attendance by properly automating operation of the aforesaid piston and cylinder assembly and by virtue of the extreme simplicity of the design of the weir, its operating mechanism and the associated workpiece separating screen assembly, the apparatus will have a long, effective and maintenance free operational life, as will hereinafter be described in detail.